Slurry Injection Systems®

The patented slurry injector system (SIS®) is our flagship product. It has proven to successfully reduce polishing defects (by up to 4X) and slurry consumption (by up to 70 percent) for many CMP and polishing processes. With 155 units presently in high-volume manufacturing on 200 and 300 mm AMAT and Ebara polishers, and with several ongoing beta tests worldwide, we are well positioned to continue to grow the company in the coming years.

Compared with the standard pad center (or multi-point) slurry application methods, SIS® is designed to have the following key advantages:

Improved slurry utilization via efficient delivery of fresh slurry to the pad-wafer interface (up to 2X reduction in slurry mean residence time).
Reduced mixing of spent slurry (and residual water) with fresh slurry supplied during polishing. This causes a higher material removal rate at the same slurry flow rate (by up to 30 percent), or an equivalent material removal rate at a lower slurry flow rate (by up to 70 percent).
Effective capture of foam (generated due to hydrogen peroxide and surfactants) and pad fragments (due to conditioning and general wear). These features result in lower wafer-level defects (by up to 4X) at standard or lower flow rates.

In most CMP tools, the slurry is applied onto the center of the pad or through a dispense arm with multiple delivery holes. As the pad rotates during polishing, centrifugal forces cause large amounts of fresh slurry to flow directly off the pad surface without entering the pad-wafer interface. This results in low slurry utilization. Moreover, as the spent slurry containing polishing by-products and pad debris mixes with the fresh slurry and re-enters the pad-wafer interface during polishing, it affects the removal rate and causes wafer-level defects. As large amounts of ultra-pure water (UPW) are used to rinse the pad surface between polishing wafers to remove slurry residue and pad debris off the pad surface, there is an appreciable amount of UPW residing on the pad surface and inside the deep grooves after rinsing. This creates a dilution effect during the next wafer polishing thereby contributing to lower removal rates.

Different from the above standard slurry application methods, SIS is designed to efficiently introduce fresh slurry inside the pad-wafer interface. SIS is placed on top of the pad during polishing while fresh slurry is applied through the SIS and over the wafer track in a uniformly thin film. This way, the slurry never goes through the air interface to be applied atop the pad thereby reducing chances of dry residue formation when the slurry is turned off periodically.

A video showing the efficient and stable operation of the SIS® on a Mirra® polisher can be seen here. A bow wave is formed in front of the injector’s leading edge, which contains used slurry and pad conditioning debris that can cause polishing defects. By squeegeeing the used slurry and the pad conditioning debris from mixing with the fresh slurry and re-entering the pad-wafer interface, SIS® is able to achieve lower polishing defects than the standard slurry application methods.

Another example video shows the slurry fluid dynamics comparison between the standard pad center application method and SIS®. To generate these videos, a fluorescent dye (4-methyl-umbelliferone) was added to the slurry which fluoresced when exposed to UV radiation. The fluorescent light was then captured by a high-resolution charged coupled device (CCD) camera, although our own VID-300® could have done just a good a job! We can see that SIS® manages to quickly spread the slurry across the pad surface and provide a much more uniform slurry distribution to the pad-wafer interface. In addition, a thick bow wave is formed in front of the injector’s leading edge since SIS® prevents the used slurry from mixing with the fresh slurry and blocks it from re-entering the pad-wafer interface. Because of the injector’s inherent barrier effect, pad conditioner oscillation has minimum impact on slurry distribution in the pad-wafer interface during polishing.

SIS® is totally passive and does not require power or any specialized software to be integrated with commercial polishers. Simple retrofit kits are available for all AMAT polishers as well as Accretech ChaMP 232 and 332, SpeedFam-IPEC 472, and Revasum 6DS polishers.

SIS® is sold to customers as a kit that can be installed, used, and removed in less than 5 minutes with maximum ease and efficiency. Each Kit is comprised of a mount and an injector unit. The mount (including the rods that connect it to the injector) is known to have a long life (more than 10 years). Based on results from our customers, the estimated life of each injector varies between 4 and 12 months depending on the consumables set and the particular polishing recipe. Once end-of-life is reached, customers are asked to replace the injector body (that is inside the injector and always in contact with the pad) with a new one. We call this the Injector Bottom Unit (IBU). The segment that touches the pad is made of PEEK.

The SIS® Kit for the AMAT RLK Prime® is shown below:
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As examples, we are showing The IBUs for Mirra® and RLK®. As mentioned above, these parts are consumables and need to be replaced periodically:

As other examples, SIS® Kits for the AMAT RLK® and Mirra®, as well as the SpeedFam-IPEC 472 are shown below:

While our primary sales strategy has been direct-to-consumer (D2C), exclusive and a very limited number of non-exclusive (regional and worldwide) distribution, sales and manufacturing licenses are available for sale to interested parties on all polisher platforms, except Ebara for which we have already sold an exclusive and perpetual license worldwide.

Please refer to the SIS® Brochure for details.

Please contact us for more information on how to schedule a beta test at your site to determine how SIS® may be able to reduce your overall COO by saving you slurry and rinse water as well as increase the overall yield of your CMP or polishing module.

We also have advanced ROI simulation models which we can share with you after our initial engagement. With OEMs, manufacturers, and distributors, we’ll be happy to discuss licensing terms and conditions.